Trader to the Stars is a collection of science fiction short stories, written by Poul William Anderson.

Three stories copyrighted from 1956 to 1962 from one of the old masters. All three stories have the space merchant Nicolas Van Rijn as the main character and what a character! He's the kind of character that you love to hate, constantly patronising everybody around him and treating women as if they some kind lower form of humans (if as humans at all). These days he would be described as a "sexist pig".

Hiding Place.
In an alien zoo ship Van Rijn needs to find the original and sentient owners of the ship who are hiding among the (alien-) animals. The question is; how does one go about getting them to reveal themselves?

Territory
A human base on a planet populated by aliens is suddenly and unprovoked attacked by the otherwise peaceful natives. Van Rijn has to flee and find allies among the natives.

The Master Key
Again the otherwise peaceful natives get hostile for no apparent reason (this time on another planet and for different reasons).

All of the stories are driven by quite interesting ideas and the other characters compensate quite nicely for Van Rijn (who can be quite annoying until you get used to him).